/*
 * Anything: A flexible and easy to use data structure that combines the 
 * characteristics of a list and a hashmap into one data structure.
 * 
 * Based on a paper by Peter Sommerlad and Marcel Rueedi on 
 * 'Do-it-yourself reflection' entered at EuroPLOP 1998.
 * 
 * This library was written completely from scratch and is based only 
 * in spirit on the original Java Anything implementation written by 
 * Andre Weinand/Marcel Rueedi in 1997/99 and enhanced by Stefan Tramm 
 * in 2006.
 * 
 * Copyright (c) 2008 Thomas Marti and others. All rights reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package any.functor.impl.func;

import any.Any;
import any.ImmutableAny;
import any.functor.interfaces.DefaultableObjecttypedFunction;
import any.util.LookupToken;

public class ElementFunction 
	extends BaseAnyFunction<Any, Object, ElementFunction> 
	implements DefaultableObjecttypedFunction<Any> {

	private final LookupToken token;

	public ElementFunction(LookupToken token) throws NullPointerException {
		if (token == null) throw new NullPointerException();
		this.token = token;
	}
	
	public ElementFunction(int index) throws IndexOutOfBoundsException {
		this.token = new LookupToken(index);
	}

	public ElementFunction(String key) throws NullPointerException {
		this.token = new LookupToken(key);
	}
	
	public Any apply(ImmutableAny from) throws NullPointerException, IllegalStateException, IndexOutOfBoundsException {
		if (hasDefault) {
			return token.access(from, defaultValue);
		} else {
			return token.access(from);
		}
	}
	
	@Override
	public String toString() {
		return "element at " + token;
	}
	
}
